cannot connect to anywhere ? all other comps are fine ?

I restored my computer back to factory settings the other day, everything went well and afterwards I could get online no probs, (we have a wireless connection}

Yesterday I tried to connect and nothing will let me go online the wifi seems fine and this computer is working online, but MY laptop just refuses to go online, it's a windows vista home premium op system and is Median computer.

O2 have tested the line but still nothing will connect me to the internet, they say if only my computer will not connect there is nothing they can do because all the other comps in the house are not having a problem ? I tried to system restore it but that came back and said something was preventing it doing a previous restore point, it does this for any restore point ? can anyone offer help with this ?

Assuming the wireless is turned ON? (sounds daft, but wouldn't be the first time!), I'd go into device manager, network adaptors and uninstall the wireless adaptor. Reboot windows and let it reinstall the driver.